Fix issue #10948509: Crash in procstats when there is no data

Not dealing with the case where there is a null list.

Also fixed some bugs I found while looking at this:

- When resetting the stats, we would use a newly computed time stamp
  for the total durations rather than the one we used to reset the
  proc/service entries.  This would result in them being able to be
  slightly > 100%.
- There was a bug in how we split a single process state into its
  per-package representation, where we would but the cloned process
  state into the new package's entry (instead of properly for its
  own package entry), to be immediately overwritten by the new
  process state we make for that package.  This could result in
  bad data for processes that have multiple packages.
- There was a bug in resetting service stats, where we wouldn't
  update the overall run timestamp, allowing that time to sometimes
  be > 100%.
- There was a bug in computing pss data for processes with multiple
  packages, where the pss data was not distributed across all of the
  activity per-package process states.
- There was a bug in computing the zram information that would cause
  it to compute the wrong value, and then never be displayed.

Finally a little code refactoring so that ProcessState and ServiceState
can now share a common implementation for the table of duration values.

Change-Id: I5e0f4e9107829b81f395dad9419c33257b4f8902
4 files changed